package Demo1;

import java.util.HashMap;
import java.util.Map;
import java.util.Set;

public class Test2 {
    public static void main(String[] args) {

        Map<String,String> country = new HashMap<String,String>();
        country.put("cn","中国");
        country.put("us","美国");
        country.put("ru","俄罗斯");

        System.out.println(country.get("cn"));

        Set<String> keys = country.keySet();
        for (String key : keys) {
            System.out.println(country.get(key));
        }
    }
}
